Tension adjustment for canvas cots



Sept. 30, 1952 P. E. SIGGERS 2,611,908

TENSION ADJUSTMENT FOR CANVAS COTS Filed May 29, 1951 INVENTOR Pln 1hP E.5i1r c er./ W W ATTURNEY Patented Sept. 30, 1952 2,611,958,; TENSIUN'ADJUSTMENTQEOR CANVAS (10181 Application-Miriam),'wil serialNor2283957 2 Claims. (Chi-dim:

(Granted? under, the, act "of,"v March 3, 1883;, asv

amended ApriP 30, 1928'; 370" 6. G. 757) The invention. described. herein, if patented, may be, manufactured, and. used. by. or. for the Government for. governmental purposes without" the payment to me'of any royalty thereon.

This invention-relates.taimpizovements in folding canvas cots and in general aims to provide a: simple but effectiveconstruction permittingan adjustment in the tension of the'canvas strip which supports the ofithe: user of the cot.

cots consist of a folding wooden frame having metal parts at the. joints and; having four legs with a canvas strip secured. hems along, four sides to the, wooden frame... This a canvas strip or which will permit the strip to be adjusted lengthwise when assembling it on the frame, or even after assembly. The present invention provides such a construction.

Referring to the accompanying drawings forming a part of this specification,

Fig. 1 is a top plan view of a cot with the improved end sticks in operative position, parts of the cot being omitted;

Fig. 2 is an enlarged fragmentary plan view of one end of the cot, with parts in section, showing the end stick adjusted for maximum fabric tension;

Fig. 3 is a view like Fig. 2 but showing the end stick adjusted for minimum fabric tension;

Fig. 4 is a side elevation of one of the end sticks; and

Fig. 5 is a perspective view of the preferred mortise and tenon joint between a side rail and the end stick.

As shown, the cot comprises a frame having legs (not illustrated), said frame consisting principally of wooden side members or rails 5 connected by metal parts, and two end sticks 6, l removably secured at the opposite ends of the side rails to hold said rails (and the legs attached thereto) spread apart. A canvas or other fabric strip 8 is stretched over the frame with hems securing it to the frame in the usual manner. Most of the details of construction are entirely conventional and hence are omitted from the drawings.

The end sticks 6, 1, which are the novel ele ments, are exactly alike, and hence a description of one willsumce for both. End stick 6 is straight and' is. substantially rectangular in. cros section with its. central; portion, 6a of" reduced width, measured horizontally, and its two" end portions 6b oblong and of about twice the: width ofitheycentral portion, Ema beveled snrface'fic ,jioining, each end. portion. 6b: with the central portion 6a. Bores 9, extend. entirely through each oblong end portion 611 at right angles, taprovide mortises, while the ends of the; si'de; rails 5 have tenons ID to fit into morti'ses 91 It will be observed that while the. oblong end. portions or enlargements 6b. are; about twice as wide as thecentralyportion tic" they have same thickness 1 vertically. The enlargements? 6b project to 'one side of the plane of' one vertical face 6d of the end stick, and said vertical face is either toward the cot, or else faces away from the cot, when the end stick is assembled. In other words, the end stick is symmetrical in its central portion 6a but'asymmetrical at its ends relative to its longitudinal axis. By turning the end sticks to present either the enlargements 6b on the inside, as in Fig. 2, or on the outside, as in Fig. 3, the outer surfaces of the central portions 6a of the two end sticks at opposite ends of the cot are either separated from each other by twice the difference in width of portions 8a and 6b, or are brought nearer together the same distance. As the hems of the canvas strip pass around these outer surfaces, the canvas strip is necessarily stretched longitudinally when the parts are in the position of Fig. 2, while its tension is lessened if the parts are in the position of Fig. 3. In lieu of turning both end sticks to present the oblong enlargements inwardly, only one end stick may be so turned.

It is contemplated that the end sticks may be about 31 in. long, with the central portions 6a three-quarters of an inch wide, measured horizontally, and one inch thick, measured vertically, and with enlarged end portions 1% in. to 1 in. wide and one inch thick, the centers of the bores 9 each being 2% in. from the nearer end of the end stick. These dimensions will permit use of the end sticks on standard Army cots. If only one end stick is turned to bring the enlarged ends 6b on the inside, a tension take-up of one-half to three-quarters of an inch is effected, but if both end sticks are so turned, a tension take-up of 1 in. to 1 in. is accomplished, the amount of take-up depending on the difference between the widths of the central portions 6a and of the enlarged ends 6b. Thus three different adjustments of canvas tension are possible without tools or change in.

3 the parts: only the positions of the end sticks are changed and this may be done by merely rotating the end sticks on their longitudinal axes, without removal from the hems.

While the end sticks could be of hardwood, the well known propensity of wood to warp, and the likelihood that an elongated wood section only three quarters of an inch wide would bend under a heavy load, suggest the use of a metallio tube of some non-rusting metal such as aluminum alloy, or one of the plastics known for its rigidity under bending moments, e. g; lignin plastics, or polystyrene or laminated'phenolics,

reinforced with metal if preferred. The described mortise and tenon joints, though desirable, are not indispensable and in lieu thereof clamps may me used to hold the side rails and end sticks together. Obviously the invention could be used with cots employing nylon or other fabrics in lieu.

of canvas strips.

It is clear that the described construction is extremely simple, is inexpensive and involves nothing that will break or get out of order. No attachments to the cot are used, nor is the cot [modified in any way except for the novel end sticks. .It will also be clear that if only a slight adjustment is desired, only one of the described end sticks need be employed, with the other end stickof conventional construction.

Having described my invention, what I claim.

.1. A folding cot of the type comprising a folding frame, and a flexible fabric connected onfour sides with said frame thereby to be stretched taut when the frame is set up; said folding frame instantially wider .than the central portion of the respective end stick and making said end portions asymmetrical relative to the longitudinal axis of the respective end stick; the flexible fabric of the respective end stick; the flexible fabric having hemsat each end, each hem receiving the central portion of an end stick so that both end sticks may be turned on their longitudinal axes to reverse the areas of the end sticks which are in contact with the ends of the side rails.

2. The invention defined in claim 1, wherein there are mortises extending laterally all the way through the enlargements, and tenons on the extreme ends of the side rails fit in said mortises from either end thereof to hold the end sticks assembled on the side rails.

PHILIP E, SIGGEBS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 34,089 Pierce Jan. 7, 1862 535,419 Scott Mar. 12, 1895 1,170,229 Ferguson Feb. 1, 1916 

